Hydrogen spillover in superwetting Ni/NiMoN Mott-Schottky heterostructures for boosting ampere-level hydrogen evolution

Realizing fast electron transfer and rapid mass transport in high current density hydrogen evolution reaction (HER) is pivotal and imperative for water electrolysis. Here, we developed Ni/NiMoN Mott-Schottky heterostructures with unique superwettability that can enhance both electron and mass transfer, greatly reducing the energy demand for water splitting. Experimental and density functional theory demonstrate that in situ grown Ni nanoparticles can optimize the dissociation of water molecules from the surface and the adsorption of H^*, facilitating the hydrogen spillover process on Ni/NiMoN. The optimized electrode delivers outstanding HER performance with an ultralow overpotential of −231.3 mV at −1000 mA cm⁻² and maintains stable operation for 1000 h in alkaline media. An anion-exchange membrane electrolyzer using Ni/NiMoN as cathode can achieve 1000 mA cm⁻² at a low voltage of 1.93 V with superstability. Our work paves an efficient way for constructing active and robust Mott-Schottky catalysts toward industrial-level hydrogen production.